How to Plan for and Optimize 802.11ac Access Points

How to Plan for and Optimize 802.11ac Access PointsWhile the benefits of 802.11ac are real and worth your consideration, actually achieving those benefits requires an understanding of the technology, engineering and deployment trade-offs during the enterprise wireless network solution’s implementation. If you don’t, you could wind up spending big bucks on a system that end-users don’t find much better than the old system. Not a good position to be in during your weekly/monthly meeting with your boss.

Fortunately, Extreme Networks has a helpful infographic that explains some of those trade offs, thus saving you from that awkward meeting.

The first point to understand is that 802.11ac has improved speed only within 30 to 40 feet of the access point. Any further than that, and you’re only going to get N speeds from that new AC AP. This partially comes from the technology/engineering trade-off designers made in choosing a higher frequency bandwidth: the higher frequency means more data can be transmitted within a given time-frame, but at shorter range. As range increases, signal strength, and thus data transmission rates drop off quickly, although other technologies in 802.11ac Wave 1 access points mitigate the problem somewhat, hence N-like speed at longer ranges.

This creates a dilemma when deciding how to deploy your 802.11ac access points when we add interference into the picture. If you place more AC APs closer together, you can guarantee AC speed across more of the covered area, but the expense of your APs interfering with each other more, potentially creating zones of poor performance. Your other option is to space your new access points further apart. This approach will minimize interference and increase the total physical space covered, but at the cost of a smaller area attaining 802.11ac speed. You therefore need to ask yourself what is more important for your enterprise: maximizing speed in specific areas, maintaining an even signal strength throughout the enterprise, or maximizing total covered area.

Another set of trade-offs comes from the channels available to first wave 802.11ac.

First, 3 of those 5 channels, however, are reserved for radar-based applications. They are called Dynamic Frequency Selection (DFS) channels. When that radar in close proximity sweeps your AP, and your AP is using one of those three channels, your network will go down. You will need to use only the two non-DFS channels if police cars and/or weather radar frequently appear near your network.

Additionally, because there are only 5 channels maximum with wave 1 AC, channel reuse will often be necessary, as will the use of those DFS channels. This will obviously create problems for some organizations that have to frequently deal with those pesky police and weather radars. If you find yourself in such a pickle before you implement an 802.11ac wireless network solution, make sure to talk with the prospective vendors about how their particular solution could solve the radar challenge.

The upside of this situation is that each 802.11ac channel is much wider than N or previous channels, so while there are fewer channels, much more data can pass through any individual AC channel. Appropriately designed and configured, AC should be able to deliver far more than N in many, if not most environments, including yours.

Now isn’t that a much nicer conversation to have with your boss?

For the Extreme Networks Blog Post containing the infographic, click here, and for the infographic itself, click here.

Doug Atkinson
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